Arp Headbolts On Rb25Det Neo From R34 Gtt

[Eclipsado]

Hi there guys, I'm from Spain and i got an Euro S13 swapped with an rb25det neo coming from an skyline r34 gtt sinister with around 12.000 miles on it

The engine is a bit modded with an hybrid gt30 turbo with t25 housings spooling really fast, got a Freddy front face intake manifold rewelded with tig welder and Q45 throttle body, running a LINKecu G4 Plug-In as an electronic management system with 2.5bar map sensor and IAT, intake...exhaust...brakes...wheels...and other things that hasn't so much importance on this thread

The head and the bottom end are stock but im changing the timing belt with a full set of gates racing and i profit to get the head out and get fully checked and mounting a metallic 3 layer headgasket as im boosting at the limit of the stock headgasket 1.2bar and arp headstuds

Got an issue with the arp headstuds as the website show two kits for the rb25det, 202-4301 and 202-4309, emailed arp and they can't tell me what is the correct application for the rb25det neo and gaved me a calculator sheet like that to fill, my knowledge doesn't go too far to get this measurements and anyway i don't think that this will be necessary as many people run arps on his neo and dont think all those people has do this

Somebody can give me some light on this?

Thanks, cheers and sorry if my english isn't enough good

[89CAL]

Are you just chasing sizing on the bolts to confirm they are for neo?

If thats the case, im suprised that ARP cant tell you. Perhaps getting in contact with an engine builder who does alot of RB engines can help

Otherwise you could probably just dummy fit the head with 2 studs in and see how they fit and make sure the nut has enough thread to clamp the head to the block

Also with the link G4, if you have a 2.5bar map sensor then it maxes out at 1.5bar of boost. Not sure if its an issue but keep in mind that the 2.5 bar is absolute pressure not gauge pressure

[Eclipsado]

Are you just chasing sizing on the bolts to confirm they are for neo?

If thats the case, im suprised that ARP cant tell you. Perhaps getting in contact with an engine builder who does alot of RB engines can help

Otherwise you could probably just dummy fit the head with 2 studs in and see how they fit and make sure the nut has enough thread to clamp the head to the block

Also with the link G4, if you have a 2.5bar map sensor then it maxes out at 1.5bar of boost. Not sure if its an issue but keep in mind that the 2.5 bar is absolute pressure not gauge pressure

Didn't bought any studs yet, just asking arp for wich its the correct application for the neo, they told me to fill that measurements sheet and send back as the two kits are different length and not interchangeable, im surprised too that arp needs this measurements to tell me wich its the correct application and i can't take because my knowledge doesn't reach that level and i don't have the necessary precision tools to make this measurements

Your idea may work but buying the two kits like a dummy to see wich its the correct ones doesn't seems good for me not talking about the money waste

Just wanted to know if someone here has mounted arp headstuds in his neo engine to know wich ones has bought and if they worked fine

I know the map sensor its 2.5 absolute pressure and i just can boost to 1.5 as the map can't read more of that, im doing this because i was boosting 1.2 with stock headgasket and if im not wrong the limit on the stock headgasket its 1.2 and my idea its get it to 1.4

Thanks for answering and for your help

Edited January 24, 2014 by Eclipsado

[boostn0199]

The stock headgasket and head bolts can take 1.5bar(21psi) pretty confortably as alot of people are still retaining the stock hg and bolts in there rb25 and neos so I wouldnt be very concerned about that.

[GTSBoy]

Yuh, don't open the engine unless you have to. 300+ rwkW on an unopened Neo is easily doable.

[scotty nm35]

Change them when the head gasket lets go.

[Eclipsado]

Yuh, don't open the engine unless you have to. 300+ rwkW on an unopened Neo is easily doable.

Thanks for the replies, my rb its at this moment at 397hp on the flywheel and im looking for more, i'm gonna upload the dyno graphic when i get home for share it

i'll appreciate all your replies but none is helping me, can we focus on the arp headstuds issue? The head is out and being on the machine workshop at this moment so the replies telling me not to change the hg not to open the engine are useless anyway as i said i'll appreciate your replies

[GTSBoy]

Then measure the bloody thing in accordance with the sheet that ARP sent you and work it out. We all thought you couldn't measure it because you hadn't taken it apart. Now that it apart a 3 year old with a crayon could probably work it out.

[scotty nm35]

I think he wants us to measure it.

Take a picture beside a ruler and we will do our best. Should work out close enough...

[Ben C34]

I'm 99.99 percent sure there is no difference between neo and non neo head bolts \ studs.

Looking at the 2 part numbers, the one ending in 9 has a slightly higher torque specified.

I would buy what ever is cheaper.

But I wouldn't. I reused my head bolts for my rb2530 with 295rwkw, so do whatever.

[Eclipsado]

I'm 99.99 percent sure there is no difference between neo and non neo head bolts \ studs.

Looking at the 2 part numbers, the one ending in 9 has a slightly higher torque specified.

I would buy what ever is cheaper.

But I wouldn't. I reused my head bolts for my rb2530 with 295rwkw, so do whatever.

Thanks dude for such a good reply, that's so useful for me